The invention relates to an apparatus for removing contents from an envelope comprising a front wall and a rear wall connected to said front wall along four folding edges, which apparatus comprises means for severing said front wall from said rear wall along three of the folding edges, means for separating the envelope from its contents and conveying means for discharging the separated envelope.
The invention further relates to a method for removing contents from an envelope by means of an envelope extraction apparatus, said envelope having a front wall and a rear wall interconnected along four folding edges, in which said front wall is severed from said rear wall along three of the folding edges, the envelope is separated from its contents and the separated envelope is discharged along an exit track.
An apparatus and method as described are known from PCT patent application published under number WO-88/01543.
A problem in machine removal of an envelope from its contents is that so far it has proved impossible in practice to ensure that under no circumstances parts of the contents are removed along with the envelope. Therefore in the known apparatus means for measuring the thickness of the envelope walls and of parts of the contents are provided for monitoring whether exclusively the envelope has been removed.
A drawback of monitoring through the measurement of thickness is that processing in a random order of postal items that are mutually different as regards the thickness of the envelopes, of the contents or of the parts of which the contents are composed is impossible.
A further drawback of measuring the thickness is that it requires expensive measuring instruments.